The effect of combining bone morphogenetic proteins -2 and -6 on osteoblastic differentiation and bone

Bone morphogenetic proteins-2 and -7 (BMP-2 and -7) are the only two members of the BMP subfamily approved to date to be used in combination with collagen type I in orthopedic surgery, although other BMPs have proven to also be highly osteoinductive. All the osteogenic BMPs signal through Smad-1/-5/-8 phosphorylation, but they have different preferences for the BMP receptors they use. Very high supraphysiological doses of BMPs have been used in the clinics for the treatment of non-union fractures and spinal fusions. Besides the high cost of these treatments, safety concerns have been recently raised. Hence there is an active field in finding alternatives to the most classical collagen + BMP-2 system. The aim of this work was to study the effect of combining two osteogenic BMPs (-2 and -6) belonging to different groups within the subfamily, and with different affinities to the existing BMP receptors. Both the growth and osteoblastic differentiation of MC3T3-E1 mouse preosteoblasts and rat bone marrow-derived mesenchymal stem cells (MSCs) under these conditions were studied, as well as in vivo ectopic bone formation when the BMPs were combined with collagen type I sponges. We show that the effect of these two growth factors is additive and that their combination might be helpful to accelerate in vivo osteogenesis while reducing the amount of each individual BMP used.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Bone marrow mesenchymal stem cells, collagen scaffold and BMP-2 for rat spinal fusio

The use of autograft for posterolateral spinal fusion, continue being considered the gold standard for the treatment of spine pathologies. However, due to complications such as donor site morbidity, increased operating time, and limited supply, the use of allograft has become an acceptable practice especially in multisegment arthrodesis or in patients with previous graft harvests. Since their use involves the risk of immune response or disease transmission and fusion rates are not as good as with autogenous bone, a variety of bone graft substitutes are being studied to obtain a better alternative. Osteoinductive growth factors, which initiate the molecular cascade of bone formation and play a key role in the development and regeneration of the skeletal system, have been shown to be effective in numerous animal studies. These molecules must be used in combination with a biomaterial to avoid their dispersion from the application site. On the other hand, it is well known that cultured bone marrow cells, harvested from adult bone marrow, may contribute to the regeneration of bone. Thus, hybrid constructs can be used as alternatives to autologous and allogenic grafts. In this study, we have evaluated different combination of cultured bone marrow cells with recombinant human osteoinductive growth factors, all of them in combination with a natural polimeric carrier, for the promotion of posterolateral spinal fusion in rats. Supported by grants from the Red de Terapia Celular (RD12/0019/0032), Spanish Government BIO2012-34960, and the Andalusian Government (P11-CVI 07245).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A model of maxilla resection to test new hybrid implants:macroporous titanium and tissue engineering elements

Maxillary bone loss in commonly found in humans, due to bone ageing, tooth loos, periodontal disease and, more severely, to trauma, radiotherapy and tumor resection. Masillofacial reconstructive surgery is a still unmet clinical demand, available therapies include grafting of autologous or heterologous bone tissue and/or the implantation of metallic plates, buy these treatments are still unable to resume form and function. The emrgence of 3D-printing technology applied to metal alloys now allows the manufacturing of customized, patient-tailored prosthetic implants. However, poor bone quiality at the implant site due to ageing or disease still hamper proper osseointegration. By combining Electron Beam Melting metal sintering and tissue engineering, we are developing hybrid maxillofacial implants, wher a metal framework of Ti6Al4V alloy confers both and appropiaate shape and mechanical stabilty, while stem cells and osteogenic molecules stimulate bone growth into the metal framework, thus pormoting osseointegration. We hereby present the in vitro work driving to the development of our hybrid maxillofacial prostheses, as well as the setting up of an in vivo model of complete maxilla full resection, created in order to test the prostheses in a preclinical studyUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A synthetic collagen-binding arg-gly-asp (rgd) biomimetic peptide enhances bone cell differentiation

RGD (arginine-glycine-aspartic acid) peptides have shown some promising abilities to promote the attachment of cells to biomaterials and to direct their differentiation. However, anchoring these peptides to the biomaterial’s surface is mandatory and usually implies several chemical linking steps. The aim of this work was to design and characterize a synthetic RGD biomimetic peptide that includes a collagen-binding domain for easy one-step functionalization of absorbable collagen sponges (ACSs), which are of frequent use in orthopaedic surgery. The stable binding of biotinylated CBD-RGD peptide loaded onto ACSs was confirmed using chemiluminisence detection after washing of the sponges. Furthermore, the effect of the peptide on MC3T3-E1 mouse preosteoblasts and rat bone marrow-derived mesenchymal stem cells (MSCs) in vitro was characterized in terms of caspase activity, proliferation, alkaline phosphatase (ALP) activity, matrix mineralization and formation of focal adhesions. Finally, a rat ectopic osteogenesis model was used to determine if the co-administration of CBD-RGD could lower the dose of BMP-2 necessary to induce bone formation. The CBD-RGD peptide was demonstrated to bind stable to ACSs, even after extensive washing. In vitro, the peptide did not induce apoptosis of the cells, but positively affected both cell growth and differentiation. It also seemed to affect the cytoskeleton arrangement of MC3T3-E1 cells, favoring the establishment of focal adhesions. At last, the in vivo experiments showed that ACSs functionalized with this peptide and loaded with a subfunctional dose of BMP-2 gave rise to ectopic bone. In conclusion. the combination of CBD-RGD with the currently used collagen/BMP system might be a promising approach to improve osteogenesis and to reduce the doses of BMPs needed in clinical orthopaedics.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Risk factors for mortality in very low birth weight infants with respiratory distress syndrome

Introducción: La expectativa de vivir de los recién nacidos de muy bajo peso (RNMBP) ha mejorado en los últimos años. Cuando estos pacientes presentan, además, enfermedad de membrana hialina (EMH), es difícil conocer con seguridad cuáles son los factores que más influyen en su mortalidad. Este trabajo tiene el objetivo de averiguar, dentro de un conjunto de variables, las más influyentes en la mortalidad desde una perspectiva multifactorial. Pacientes y métodos: Se tomó una muestra de 209 RNMBP con EMH nacidos en un período amplio, 15 años y 7 meses. Se consideraron las variables: "fecha de parto", "grado de enfermedad de membrana hialina", "sexo", "peso al nacimiento", "semanas de gestación", "procedencia", "administración de corticoides prenatales", "tipo de gestación", "tipo de parto", "momento de la amniorrexis", "puntuación del test de Apgar al minuto y a los 5 min", "administración de surfactante", "horas de vida en la administración de la primera dosis de surfactante" y "sepsis precoz". Siguiendo la metodología de selección de variables de Hosmer-Lemeshow se realizó un análisis de regresión logística múltiple. Resultados: Resultaron significativas las variables peso al nacimiento; test de Apgar, 5; corticoides prenatales, grado de membrana hialina y tratamiento con agente tensioactivo, quedando la importancia del resto de las variables diluida en ellas. Conclusiones: El incremento de peso y el test de Apgar a los 5 min, la administración de agente tensioactivo y corticoides, así como un grado bajo de membrana hialina hacen que la mortalidad disminuya. El modelo de regresión logística encontrado cuantifica cómo actúan estos factores y permite estimar la probabilidad de fallecer para un nuevo RNMBP con EMH.Introduction: In the last few years the life expectancy of very low birth weight (VLBW) infants has improved. When these patients have respiratory distress syndrome, it is difficult to know with any certainty which factors have the greatest influence on mortality. The aim of this study was to determine which variables, among a series, have the greatest influence on mortality from a multivariate perspective. Patients and methods: A sample of 209 VLBW infants born over a long period (15 years and 7 months) was studied. The following variables were analyzed: date of birth, degree of respiratory distress syndrome, sex, birth weight, weeks of gestation, born within or elsewhere, prenatal corticoid administration, type of gestation, type of delivery, amniorrhexis time, Apgar test at 1 and 5 minutes, surfactant administration, hours of life at which the first dose of surfactant was administered, and early sepsis. A multiple logistic regression analysis was developed using Hosmer-Lemeshow methodology. Results: The following variables were identified as significant: birth weight, Apgar test at 5 minutes, prenatal corticoids, degree of respiratory distress syndrome, and surfactant administration. The remaining variables were less important in the multivariate analysis. Conclusions: Higher birth weight and Apgar score at 5 minutes, prenatal corticoid and surfactant administration, and a lower degree of respiratory distress syndrome reduce mortality. The logistic regression model used quantifies how these factors behave and allows the probability of mortality in VLBW infants with respiratory distress syndrome to be estimated.Depto. de Estadística e Investigación OperativaFac. de Ciencias MatemáticasTRUEpu

Activating transcription factor 6 derepression mediates neuroprotection in Huntington disease

Deregulated protein and Ca2+ homeostasis underlie synaptic dysfunction and neurodegeneration in Huntington disease (HD); however, the factors that disrupt homeostasis are not fully understood. Here, we determined that expression of downstream regulatory element antagonist modulator (DREAM), a multifunctional Ca2+-binding protein, is reduced in murine in vivo and in vitro HD models and in HD patients. DREAM downregulation was observed early after birth and was associated with endogenous neuroprotection. In the R6/2 mouse HD model, induced DREAM haplodeficiency or blockade of DREAM activity by chronic administration of the drug repaglinide delayed onset of motor dysfunction, reduced striatal atrophy, and prolonged life span. DREAM-related neuroprotection was linked to an interaction between DREAM and the unfolded protein response (UPR) sensor activating transcription factor 6 (ATF6). Repaglinide blocked this interaction and enhanced ATF6 processing and nuclear accumulation of transcriptionally active ATF6, improving prosurvival UPR function in striatal neurons. Together, our results identify a role for DREAM silencing in the activation of ATF6 signaling, which promotes early neuroprotection in HDThis work was funded by the Instituto de Salud Carlos III/CIBERNED (to J.R. Naranjo, B. Mellström, and A. Rábano), FISS-RIC RD12/0042/0019 (to C. Valenzuela), Madrid regional government/Neurodegmodels (to J.R. Naranjo), MINECO grants SAF2010-21784 and SAF2014-53412-R (to J.R. Naranjo), SAF2012-32209 (to M. Gutierrez-Rodriguez), SAF2010-14916 and SAF2013-45800-R (to C. Valenzuela), and a grant from the Swedish Research Council (J.Y. Li

Osteogenic molecules for clinical applications: improving the BMP-collagen system

Among the osteogenic growth factors used for bone tissue engineering, bone morphogenetic proteins (BMPs) are the most extensively studied for use in orthopaedic surgery. BMP-2 and BMP-7 have been widely investigated for developing therapeutic strategies and are the only two approved for use in several clinical applications. Due to the chemical and biological characteristics of these molecules, their authorised uses are always in combination with a carrier based on collagen type I. Although the use of these growth factors is considered safe in the short term, the very high doses needed to obtain significant osteoinduction make these treatments expensive and their long-term safety uncertain, since they are highly pleiotropic and have the capacity to induce ectopic ossification in the surrounding tissues. Therefore it is necessary to improve the currently used BMP-collagen system in terms of efficiency, biosecurity and costs. There are several strategies to increase the clinical effectiveness of these treatments. In this review we summarize the most promising results and our related work focused on this field through two different approaches: i) the development of recombinant BMPs with additional features, and ii) complementing these systems with other growth factors or molecules to enhance or accelerate osteogenesi

Osteogenic molecules for clinical applications: improving the BMP-collagen system

Among the osteogenic growth factors used for bone tissue engineering, bone morphogenetic proteins (BMPs) are the most extensively studied for use in orthopaedic surgery. BMP-2 and BMP-7 have been widely investigated for developing therapeutic strategies and are the only two approved for use in several clinical applications. Due to the chemical and biological characteristics of these molecules, their authorised uses are always in combination with a carrier based on collagen type I. Although the use of these growth factors is considered safe in the short term, the very high doses needed to obtain significant osteoinduction make these treatments expensive and their long-term safety uncertain, since they are highly pleiotropic and have the capacity to induce ectopic ossification in the surrounding tissues. Therefore it is necessary to improve the currently used BMP-collagen system in terms of efficiency, biosecurity and costs. There are several strategies to increase the clinical effectiveness of these treatments. In this review we summarize the most promising results and our related work focused on this field through two different approaches: i) the development of recombinant BMPs with additional features, and ii) complementing these systems with other growth factors or molecules to enhance or accelerate osteogenesi

Factores en la morbilidad respiratoria de los recién nacidos de muy bajo peso con membrana hialina

Introduction: Very low birth weight (VLBW) infants, with a birth weight below 1500 g and a structurally immature lung, are at high risk for developing bronchopulmonary dysplasia. This risk is even higher if respiratory distress syndrome is present. Other acute lung diseases, such as air leak and pulmonary hemorrhage, can also be present. The aim of this study was to analyze the statistical relevance of several neonatal factors in the development of pulmonary complications in a sample of VLBW infants with respiratory distress syndrome. Patients and methods: A total of 209 VLBW infants with respiratory distress syndrome were studied. The variables analyzed were delivery date, respiratory distress syndrome grade, sex, birth weight, gestational age, referral (from within the hospital or elsewhere), prenatal corticosteroid administration, type of gestation, type of delivery, amniorrhexis time, Apgar test at 1 and 5 minutes, surfactant administration, hours of life at which the first dose of surfactant was administered, and early sepsis. A multiple logistic regression analysis was developed using Hosmer-Lemeshow methodology. Results: In the multivariate analysis, air leak was related to respiratory distress syndrome grade and surfactant administration. Pulmonary hemorrhage was related to lower birth weight and absence of prenatal corticosteroid administration. Bronchopulmonary dysplasia was related to single pregnancies, absence of prenatal corticosteroid administration, lower birth weight, lower Apgar score at 1 minute, and higher respiratory distress syndrome grade. Conclusions: Respiratory morbidity in VLBW infants with respiratory distress syndrome could be influenced by several interrelated intrinsic and extrinsic variable